Sample autoloader for use with an analytical combustion furnace

ABSTRACT

A sample autoloader loads a sample into a furnace and removes a sample from the furnace. The sample autoloader includes a sealing plate for sealing the furnace. The sample autoloader also includes a mechanism for pushing a sample into the furnace and removing a sample from the furnace. The sample autoloader may include a hotel which stores sample containers for automatic loading and a container which receives spent sample containers.

BACKGROUND OF THE INVENTION

The present invention relates to sample loaders and, more particularly,to an automatic sample loader for a horizontal analytical furnace.

Horizontal analytic furnaces are well known. An example of such afurnace is disclosed in U.S. Pat. No. 5,064,617 entitled COMBUSTIONSYSTEM issued to O'Brien et al. on Nov. 12, 1991. These furnaces aretypically manually loaded with a sample. However, manual loading is timeconsuming and uncomfortable for the loader due to the high temperaturewithin the combustion furnace and the high temperature of samplecontainers which are removed from the furnace.

Automatic sample loaders are known which mechanically load samples intoan analytical combustion furnace. However, such loaders do notadequately seal the furnace following introduction of a sample.Accordingly, atmospheric contaminants such as nitrogen enter into thefurnace and detrimentally effect the results of the analysis performedusing analytical furnace. Additionally, these automatic loaders do notadequately provide for loading of sample containers and unloading hotspent containers.

SUMMARY OF THE INVENTION

The system of the present invention overcomes the difficultiesencountered by the prior art. According to one aspect of the invention,an automatic loader seals the furnace following introduction of a sampleinto the furnace. Accordingly, the autoloader reduces the admission ofcontaminants into the furnace.

According to another aspect of the invention, the mechanism which pushesa sample container into the furnace hot zone is retracted to a coolerregion of the furnace during combustion. The mechanism returns to thehot zone to retrieve the used boat after analysis is complete.Accordingly, the mechanism remains in the furnace after the furnace issealed and until analysis is completed.

According to yet another aspect of the invention, an autoloaderaccording to the invention delivers samples from a boat hotel to thefurnace. The autoloader also removes the hot spent boats from thefurnace and disposes them in a container where they can cool for furtheruse or disposal.

The system according to the invention provides an efficient loader formoving samples into an analytical combustion furnace. Additionally, theautoloader provides a method of removing spent samples so that a newsample may be placed in the analytical furnace. Furthermore, theautoloader provides an automatic sealing mechanism which allowsintroduction of a sample into a furnace and subsequent sealing of thefurnace to prevent the introduction of atmospheric contaminants to theanalytical process.

These and other features, objects and advantages of the presentinvention will become apparent upon reading the following descriptionthereof, together with reference to the accompanying drawings in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front perspective view of an autoloader according to theinvention and a fragmentary perspective view of a horizontal combustionfurnace with which the autoloader is used;

FIG. 2 is a partially cut-away front elevational view of a heightadjustment mechanism for the autoloader according to FIG. 1 with theautoloader platform shown in fragmentary form;

FIG. 3 is a side elevational view of the autoloader and furnaceaccording to FIG. 1;

FIG. 4 is a fragmentary perspective view of a boat launch assembly forthe autoloader according to FIG. 1;

FIG. 5 is a top perspective view of a hotel carriage assembly for theautoloader according to FIG. 1, wherein the autoloader platform is shownin fragmentary form;

FIG. 6 is a perspective view of a push rod assembly, an elevatorassembly and a boat hotel for the autoloader according to FIG. 1;

FIG. 7 is a front elevational view of the autoloader with the boathotel, boat elevator box, purge chamber, and furnace chamber cut away;

FIG. 8 is a side elevational view of an elevator for the autoloaderaccording to FIG. 1, with the guide rails therefor shown in fragmentaryform;

FIG. 9 is a fragmentary side elevational view of an elevator box shownits rest state;

FIG. 10 is a fragmentary front elevational view of a box, arms and pushrod of the elevator according to FIG. 9;

FIG. 11 is a fragmentary perspective view of a boat launch assembly forthe autoloader according to FIG. 1;

FIG. 12 is a fragmentary perspective view of the autoloader spent boatcontainer according to FIG. 1 with the boat elevator at its lowestposition;

FIG. 13 is a top plan view of a boat launch assembly for the autoloaderaccording to FIG. 1;

FIG. 14 is a fragmentary side elevational view of a boat retrieval rodand hook for the boat launch assembly according to FIG. 13;

FIG. 15 is a fragmentary side elevational view of an elevator, a boatretrieval rod and boat according to FIG. 1, with the retrieval rod shownin its "down" position;

FIG. 16 is a side elevational view of the elevator, the boat retrievalrod and the boat according to FIG. 15, with the retrieval rod shown inits "up" position;

FIG. 17 is an exploded, partially fragmentary sectional view of thesealing block, a furnace attachment block, and a purge chamber accordingto FIG. 1;

FIG. 18 is a fragmentary, partially cross sectional side elevationalview of the push rod with the sealing block according to FIG. 17;

FIG. 19 is a circuit schematic in block diagram form of an electroniccontrol circuit and pneumatic control circuit for the autoloaderaccording to FIG. 1;

FIG. 20A and FIG. 20B are a flow diagram of the control circuitaccording to FIG. 19;

FIG. 21 is a front elevational view of a boat launch assembly accordingto FIG. 1, partially cut-away, with the boat retrieval arm placing aspent boat onto the upper position of the elevator;

FIG. 22 is a front elevation view of the boat launch according to FIG.21 with the retrieval rod in a rest position;

FIG. 23 is a front elevational view of the boat launch assemblyaccording to FIG. 21 with the retrieval rod pushing the next boat offthe elevator into the purge position of the furnace;

FIG. 24 is a fragmentary front perspective view of the boat launchassembly according to FIG. 11 with the furnace sealing block, theautoloader attachment block and the purge chamber in abutting position;

FIG. 25 is a front elevational view of the boat launch assemblyaccording to FIG. 21 with the furnace sealing block in a sealed positionand the retrieval rod in the rest position;

FIG. 26 is a front elevational view of the boat launch assemblyaccording to FIG. 21 with the retrieval rod pushing the boat into thefurnace according to FIG. 1; and

FIG. 27 is a front elevation view of the boat launch assembly accordingto FIG. 21 with the boat retrieval rod fully inserted into the furnace.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference initially to FIG. 1, an autoloader 50 is illustratedwhich automatically loads boats 52 (FIG. 2) into an analyzer/furnace 54(FIG. 1). The autoloader may be used with a commercially available LecoCNS2000 analyzer. The autoloader includes a boat hotel 56 (bestillustrated in FIG. 3) which stores boats 52 having samples to beanalyzed therein. Boat hotel 52 is mounted to a boat hotel carriage 58(best illustrated in FIG. 5) which moves hotel 56 forward and backwardon a platform 60 under the control of a motor 59. A pneumatic boatpusher 62 (FIG. 7) pushes boats 52 out of hotel 56 and onto a lowershelf 68 of an elevator 64. Boat pusher 62 is moved vertically by a DCmotor 63 (FIG. 6). Elevator 64 is moved vertically by a DC motor 65. Theboat elevator provides the vertical transportation of boats 52 withinthe autoloader. Elevator 64 includes a pneumatic tilter 79 (FIG. 8) fordispensing spent boats 52 into a spent boat container 86 (FIG. 12). Ashoot 84 is positioned below elevator 64 for deflecting spent boats fromelevator 54 into container 86.

The autoloader includes a boat launch assembly 68 which seals a purgechamber 90 (FIG. 1) of analytical furnace 54 and provides horizontaltransport of boats 52 within the analytical furnace and purge chamber.The boat launcher includes an autoloader furnace attachment block 72 forabutting contact with purge chamber 90. The boat launcher assembly alsoincludes a furnace sealing plate 70 which is selectively moved to asealing position abutting autoloader furnace attachment block 72. A boatretrieval rod 76 (FIG. 11) extends through sealing plate 70. Theretrieval rod is moved laterally by a motor 77 for retrieving boats fromanalyzer/furnace 54 and loading the boats onto the top shelf 78 (FIG.21) of elevator 64. The boat retrieval rod is also moved laterally toload boats 52 from the lower shelf 68 of elevator 64 intoanalyzer/furnace 54 (FIG. 23).

Somewhat more particularly, autoloader 50 includes a frame 100 (FIG. 1).The frame includes a lower frame section 101 and an upper frame section103, and a boat launcher frame 99. Lower frame section 101 includes abase 102. A platform 60 of an upper frame section is supported by threeleveling columns 104-106. Leveling columns 104-106 are verticallyadjustable to align autoloader 50 with purge chamber 90. Each ofleveling columns includes a cylindrical post 107 (FIG. 2) fixedlysecured to base 102. Post 107 has a threaded aperture 109 at the topwhich receives one threaded end of a shaft 111. Shaft 111 includes ashelf 113 circumscribing the shaft. A grommet 121 includes lower halfsection 117 and an upper half section 119, each half section includingthreads for interconnecting the half sections through an aperture inplatform 60. Shaft 111 is inserted through grommet 121 such that thelower half sits on shelf 113. A handle 123 is fixedly secured to shaft111, and may be integrally formed therewith. Handle 123 is used torotate shaft 111, which effects vertical movement of platform 60relative to cylinder 117.

The upper frame section 103 includes platform 60, a back wall 108 andvertical supports 112 and 114. Back wall 108 (FIGS. 1 and 3) isconnected to platform 60. Back wall 108 includes an opening 110 (FIG. 1)for receipt of hotel 56. Opening 110 allows the hotel to move throughwall 108. A housing 112 (FIG. 3) is connected to back wall 108 by anysuitable conventional means. Circuitry and pneumatic devices forcontrolling movement of the components of the autoloader are mountedwithin housing 112. Back wall 108, together with vertical supports 114(FIG. 1) and 116, fixedly support launch assembly 68 on platform 60.

Launch assembly 68 includes a frame 99. Frame 99 has a front beam 120and a rear beam 122, each having an L-shaped cross section, as bestillustrated in FIG. 4. Beams 120 and 122 may be formed from any suitablematerial, such as extruded aluminum. The beams extend between an endmember 124 and autoloader furnace attachment block 72. End member 124and attachment block 72 may be formed from any suitable material such asstainless steel or aluminum. The front and rear beams are mounted on endmember 124 and autoloader furnace attachment block 72 by any suitableconventional method to form a rigid launch frame.

Still more particularly, autoloader 50 includes a boat hotel carriageassembly 58 (FIGS. 3 and 5) for movement on vertically stacked,juxtapositions guide rails 125 and 127. Opposite ends of guide rails 125and 127 are mounted to platform 60 using mounting brackets 129 and 131.A guide rail trolley mechanism 128 is movingly attached to guide rails125 and 127 in any suitable, conventional manner. A generallyrectangular platform 126 is secured to trolley mechanism 128 using anysuitable means, such as threaded fasteners (not shown). Trolleymechanism 128 also includes a clamp 130 which is fixedly connected to atiming belt 134 using threaded fasteners 133 (FIG. 3). The timing beltmay be provided by any suitable belt such as a stainless cable withpolyurethane. Trolley mechanism 128 moves with timing belt 134 on theguide rails 125, 127.

DC motor 59 is fixedly attached to platform 60 in any suitableconventional manner for moving timing belt 134. DC motor 59 is providedby any suitable, commercially available motor, such as a DC brushlessgear motor with an optical encoder. The DC motor includes ashaft/sprocket 138. Timing belt 134 engages shaft/sprocket 138. Thetiming belt also engages a pulley 139 which is fixedly secured toplatform 60. Motor 59 effects precise rotating movement of timing belt134 on pulley 139 and shaft sprocket 138. The trolley mechanism 128 isclamped to belt 134 such that the trolley moves with the belt.

Platform 126 includes mounting devices for facilitating attachment ofhotel 56 to platform 126. An orthogonally projecting post 140 is a firstmounting device. Post 140 includes a disc 142 and a concentric smallerdiameter rod 144. Rod 144 is attached to platform 126 by any suitableconventional means. Disc 142 is attached to an end of rod 144 and may beintegrally formed with rod 144. A projecting anchor 146, having a head148, defines a groove 150 between head 148 and end 152 of platform 126.

Boat hotel 56 includes a generally rectangular housing 160 (FIG. 3).Housing 160 includes a handle 152 extending from a top wall 164 thereof.A sidewall 166 and a sidewall 168 extend orthogonally from top wall 164.A bottom wall 170 extends between sidewalls 166 and 168. Hotel 56 alsoincludes shelves 172-177 which extend parallel to top wall 164 andbottom wall 170 between sidewalls 166 and 168. The side walls areattached to top wall 164, bottom wall 170, and shelves 172-177 by anysuitable construction, such as threaded fasteners inserted through theside walls and received in the horizontal walls/shelves. The shelves maycontain ribs (not shown) which define storage positions on the shelvesfor boats 52. Each boat is accurately positioned when placed between twoof such ribs. The housing may be made of any suitable material such asextruded aluminum. A hinged conventional snap fastener 180 (FIGS. 1 and3) is mounted to sidewall 166 in any suitable conventional manner suchas by threaded fasteners. Snap connector 180 may be provided by anysuitable, conventional snap-connector which will engage anchor 146 (FIG.5). A T-shaped recess 182 (FIG. 6) is provided in a wall 166 to receivepost 140.

Autoloader 50 also includes a boat pusher 62 (FIGS. 1, 3 and 6) mountedfor vertical movement on the back wall 108 such that it may bepositioned adjacent boats 52 in different rows of hotel 56. Juxtaposedguide rails 186 (FIG. 3) and 188 are vertically mounted on back wall 108to provide a track for the boat pusher. The guide rails are mounted tothe front face 189 (FIG. 1) of the back wall 108 using mounting brackets190 and 192. Guide rail mounting brackets 190 and 192 may be mounted toback wall 108 using any suitable conventional means such as threadedfasteners or welding. A trolley mechanism 194 (FIG. 7) securely engagesguide rails 186 and 188. The trolley mechanism includes a bracket 195(FIG. 6) which extends through opening 110. A clamp 197 is fixedlysecured to bracket 195 and to a timing belt 198. Timing belt 198 may beprovided by any suitable chain means such as a stainless cable withpolyurethane. Vertical movement of the timing belt thus effects movementof trolley 194 upwardly and downwardly on guide rails 186 and 188.

A DC motor 63 includes a shaft/sprocket 202 extending outwardlytherefrom for effecting movement of timing belt 198. Shaft/sprocket 202includes teeth for engaging timing belt 198 which extends aroundshaft/sprocket 202 and a pulley 204. Pulley 204 is rotatably mounted toa block 206. Block 206 is mounted to a bracket 207 by any suitableconventional mean such as welding. Bracket 207 is mounted to the backface 209 of back wall 108 in any suitable conventional manner, such asby welding or using threaded fasteners.

The pneumatic push rod 62 includes a cylinder 208 (FIG. 7) and a pushrod pin 209. The push rod cylinder 208 is mounted to bracket 195. Thepush rod cylinder is mounted orthogonally with respect to guide rails186 and 188 such that push rod pin 209 will move orthogonally throughhotel 56. Push rod cylinder 208 receives fluid control signals throughtube 210 and 212 for moving push rod pin 209. Forward motion pneumaticcontrol signals are received through tube 210 and withdrawal controlsignals are received through tube 212. The control signals may bereceived from any suitable source, such as a compressor or bottled air(not shown). The fluid control signals input to push rod cylinder 208effect movement of push rod pin 209 through housing 56 such that boats52 are pushed onto lower shelf 68 of elevator 64. When the controlsignal ceases, the push rod pin returns to its rest state which is theposition illustrated in solid in FIG. 7.

Elevator 64 is slidingly mounted on juxtaposed guide rails 220 (FIG. 6)and 222 which are mounted vertically to the front face 189 of back wall108 using mounting brackets 224 (FIG. 7) and 226. Mounting brackets 224and 226 are mounted to back wall 108 by any suitable conventional means,such as by welding or using threaded fasteners. A guide rail trolleymechanism 228 (FIG. 8) securely, movably engages rails 220, 222 forupward and downward movement of elevator 64 thereon. Trolley 228includes a mounting bracket and clamp 229 (FIG. 6) which extends throughopening 110 and is fixedly secured to a timing belt 233. Trolleymechanism 228 thus moves with timing belt 233. Timing belt 233 engagestoothed sprockets 235 and 236. Sprocket 235 is supported on the shaft ofD.C. motor 65. Sprocket 236 is rotatably secured to a block 243. Block243 is mounted by any suitable conventional means to a bracket 245.Bracket 245 is mounted on the back face 209 of back wall 108 by anysuitable conventional means such as welding or using threaded fasteners.The elevator includes a frame 230 (FIG. 8) attached to trolley mechanism228 using any suitable conventional means such as threaded fasteners.Frame 230 includes a base 231 and integral arms 232, 234 projectingorthogonally therefrom. A pivot axle 236 extends through the distal endsof arms 232 and 234 (FIG. 10). A box 238 of elevator 64 is hingedlyattached to pivot axle 236 and rests on arms 232, 234 in a rest stateillustrated in FIG. 9. Box 238 includes a top shelf 78 and a bottomshelf 68. A front wall 244 and a back wall 246 extend orthogonallybetween top shelf 78 and bottom shelf 68. The ends of box 238 are opensuch that boats may be placed on and removed from lower shelf 68.

A foot 248 extends downwardly from bottom shelf 78 and includes a boreextending laterally therethrough. A pneumatic tilter 79 is connected tofoot 248. Pneumatic tilter 79 includes a cylinder 251 and a pin 253. Pin253 is attached to foot 248 by a U-shaped bracket 259 which is attachedto end 261 of pin 253. An axle 251 extends through bracket 259 and foot248. Box 238 pivots on axles 255 and 236 to move between the dump andrest positions, and thus to dump boats 52 from top shelf 78. End 263 ofcylinder 251 is pivotally secured to outwardly projecting shoulders of aU-shaped bracket 256. An axle 274 extends through bracket 256 andcylinder 257 to provide a pivot point tilting rod 250 when the hotel ismoved between the rest and the dump positions. Cylinder 251 receivescontrol signals through tube 256 for moving pin 253 from its rest positto its fully extended position, and thus tilting box 238 (FIG. 8). Fluidcontrol signals for returning pin 253 and elevator box 238 to the restposition are input through a tube 257.

A spent boat container 86 (FIG. 1) is positioned on base 102 belowelevator 64 to receive spent boats 52 dumped from the top shelf 78 ofthe elevator. The spent boat container 86 may be provided by anysuitable, conventional container for receipt of hot boats. The containeris positioned below an opening 262 (FIG. 5) in platform 60. A guard rail264 (FIG. 12) preferably circumscribes, a extends through, opening 262to direct boats to shoot 84. Shoot 84 deflects boats into container 86.Shoot 84 and guard rail 264 may be of any suitable construction, such asintegrally formed of a suitable metal. Shoot 84 may alternatively beprovided by any suitable means such as a single metal plate angledtoward container 86 or a pair of plates having a V-shaped profile and anopening at the bottom. The container provides a collection and coolingfacility for spent boats unloaded from the furnace by the autoloader.The container preferably has sufficient capacity to hold all thecontainers in hotel 56.

Launch assembly 68 includes horizontal, laterally spaced guide rails 279(FIG. 13) and 281 extending between end block 124 and autoloaderattachment block 72. The guide rails are fixedly mounted on block 72 andmember 124 by any suitable, conventional means, such as by threadedfasteners secured to the ends on the rods. A boat retrieval rod andsealing block carriage 278 is supported for lateral movement on rails279 and 281. Carriage 278 includes a guide block 300 and furnace sealingplate 70. Guide block 300 and furnace sealing plate 70 are connected bybeams 302 and 304. The guide blocks and beams provide a rigid carriageassembly for movement on the guide rails

A motor 77 (FIG. 1), including a shaft and sprocket 286, is mounted tofurnace sealing plate 70 (as best illustrated in FIG. 11). The motor maybe attached using a U-shaped mounting bracket 291 assembled to furnacesealing plate 70 in any suitable, conventional manner, such as bywelding or use of threaded fasteners (not shown). A pulley 290 (FIG. 1),including a sprocket 292 and a pulley block 294, are attached to guideblock 300. Sprocket 292 is rotatably supported on the pulley block 294.Block 294 is, in turn, connected to guide block 300 by conventionalmeans, such as by welding or using threaded fasteners. Sprockets 292 and286 are operably connected by a timing belt 282, such that the timingbelt rotates on sprockets 286 and 292 when motor 77 operates.

A guide rail support block 316 is also slidingly engaged on spaced guiderails 279 and 281. A clamp 314 (FIG. 7) is attached to support block 316by conventional means, such as by welding or threaded fasteners. Clamp314 fixedly clamps onto timing belt 282. Timing belt 282 may be providedby any suitable, conventional means such as a stainless cable andpolyurethane. Support block 316 moves relative to the retrieval rod andsealing plate carriage 278 when motor 77 moves timing belt 282 moves.

The boat retrieval rod 76 (FIG. 3) passes through support block 316 andis secured to a pneumatic rotor 317. Boat retrieval rod is preferablyconstructed of 303 stainless steel. Rotor 317 is fixedly mounted onsupport block 316. The boat retrieval rod also extends through furnacesealing plate 70. The retrieval rod includes an L-shaped hook 322 (FIG.14) on the distal end 324. The hook is preferably constructed from sheetstainless steel bent to be L-shaped. The hook may be secured on the endof rod 76 by any suitable conventional means such as threaded fasteners326. The threaded fasteners are preferably constructed of stainlesssteel. The center axis of hook 322 is preferably laterally offset fromthe center axis A1, of rod 76. Accordingly, the hook 322 may be widerthan rod 76 to provide a wide impact area for engagement with boat 52 inthe down position (FIG. 15), and move out of the way of boat 52 when rod76 rotates to the up position illustrated in FIG. 16.

The boat retrieval rod 76 is rotated under the control of a pneumaticrotary actuator 400. Rotor 400 provides 90° rotation of rod 76. Rotator400 is fixedly mounted to guide block 316 by any suitable, conventionalmeans. Rotor 400, guide block 316 and rod 76 thus slide longitudinallysimultaneously to move the retrieval rod into and out ofanalyzer/furnace 54. The rotor receives clockwise rotation pneumaticcontrol signals through an input tube 401 and counter clockwisepneumatic control signals through a return tube 403.

The furnace sealing plate 70 includes a bore 328 (FIG. 17) extendingtransversely therethrough for receipt of retrieval rod 76 and sealingmembers therefor. Retrieval rod 76 and furnace sealing plate 70 aresealed as illustrated by FIG. 18 to prevent the passage of gas throughthe sealing plate. The seal is provided by a Teflon spring seal 338(FIGS. 17 and 18) a bushing 340 and a mounting bracket 342. Acounterbore 334 is concentric with bore 328 and receives teflon springseal 338 when it is inserted into counterbore 334. Mounting bracket 342is attached to sealing plate 70 to secure teflon seal 338 in counterbore 334. Mounting bracket 342 may be constructed of any suitablematerial such as brass. The mounting bracket may be secured by anyconventional means such as by threaded fasteners 344 and 346 which arereceived through bracket 342 and secured in threaded apertures 348 and350. Sealing plate 70 also includes a counterbore 336 which isconcentric with bore 328 and receives bushing 340. The bushing may beconstructed of any suitable material such as aluminum. A low frictiontape (not shown), such as a teflon or floral polymer tape, is preferablyattached to the inside diameter of disk 340 such that it is positionedbetween disc 340 and rod 76. Disc 340 is secured in counterbore 336 byany conventional means, such as by washer 352 and threaded fastener 354.Threaded fastener 354 is received in a threaded aperture 356 in sealingplate 70. Sealing plate 70 also includes a circular channel 358. Channel358 receives an 0-ring 359. 0-ring 359 provides a seal between sealingplate 70 and autoloader furnace attachment block 72.

The sealing plate 70, with its associated carriage assembly, is movedbetween an open position and a closed position by pneumatic devices 380,382 (FIGS. 11 and 13). Pneumatic devices 380 and 382 each include acylinder 384 and a rod 386. Cylinder 384 is secured to block 70 by anysuitable, conventional means such as by a L-shaped bracket 388 (FIG. 11)mounted to the cylinder and block 70 by threaded fasteners 387. Rod 386is secured to autoloader furnace attachment block 72 by a U-shapedbracket 389. Bracket 389 is secured to block 72 by any suitable meanssuch as threaded fasteners (not shown). The bracket is secured to rod386 by conventional male and female threaded fasteners. The pneumaticcylinder receives fluid control signals from a control signal source 470(FIG. 19). Control signals for moving plate 70 from the open to theclosed position are input through a supply tube 390 (FIG. 11). Controlsignals for moving plate 70 from the closed to the open position areinput through a tube 392.

Purge chamber 90 is secured to face 430 (FIG. 4) of furnace attachmentblock 72. The purge chamber includes housing 360 having a central bore361 aligned with a furnace tube 362 (FIG. 7) of analyzer/furnace 54 anda bore 365 through sealing plate 72. The purge chamber also includes acircumscribing channel 364. An 0-ring 366 is received in channel 364 forsealing the purge chamber against autoloader furnace attachment block72.

The purge chamber 90 is locked into engagement with autoloaderattachment block 72. To accomplish a secure lock with a tight seal, atop snap-lock 410 and a bottom snap-lock 412 are mounted on a top wall414 and a bottom wall 416 of the purge chamber 90. The snap lock may beprovided by any suitable, commercially available snap lock. The snaplocks are connected to purge chamber 90 by any suitable conventionalmeans such as by threaded fasteners or welding. A U-shaped bracket 418for receipt of snap connector 410 is mounted at the top of block 72 byany suitable conventional means such as threaded fasteners. A U-shapedbracket 420 is mounted to the bottom of block 72 for receipt ofsnap-lock 412. The bracket may be mounted by any conventional means suchas by threaded fasteners or welding.

The control circuit for the autoloader will now be described withreference to FIG. 19. The autoloader is controlled by a microcontroller446. Microcontroller 446 is preferably implemented by a personalcomputer used to control the analyzer/furnace 54, although it may beimplemented using any commercially available microcontroller. Themicrocontroller is connected to an extended bus interface 447. Interface447 directs control signals from microcontroller 446 to a motorcontroller 449 or a digital input/output (I/O) circuit 457.

Motor controller 449 is responsive to control signals from extended bus447 to control motor driver 463. Motor driver 463 controls interface 462to selectively supply positive or negative power to motor 63. Motordriver 463 also controls interface 460 to selectively supply positive ornegative power to motor 65. The interface 462 is also connected tomicroswitch 464. Interface 462 is responsive to control signals frommicroswitch 464 to supply control signals, via motor driver 463 andmotor controller 449, to extended bus 447 indicating when microswitch464 is closed. Interface 460 is similarly connected to microswitch 468and supplies a control signal via motor driver 463 and 449 to extendedbus 447 which indicate when microswitch 468 is closed.

Motor driver 461 is connected to interface 458 and interface 448.Interface 458 is responsive to control signals from motor driver 461 toselectively supply positive or negative power to motor 77. The interfaceprovides positive or negative power to the motor to control thedirection of motor operation. Interface 448 is responsive to controlsignals from motor driver 461 to provide positive or negative power tomotor 59. Motor 59 is responsive to positive and negative power supplyto move in a forward and backward direction, respectively. Interface 458is connected to microswitch 472 and supplies control signals to extendedbus 447 via motor controller 449 and motor driver 461 to indicate whenthe microswitch is closed. Interface 448 is connected to microswitch 452to receive a control signal therefrom. The control signals 452 aresupplied via interface 448 and motor driver 461 to extended bus 447which indicate when microswitch 452 is closed.

Microswitches 452, 464, 468 and 472 are used to set the zero positionfor trolley mechanism 128, trolley mechanism 194, trolley mechanism 228,and support 316, respectively. Upon power up, each of these devices willmove to the position which closes its associated microswitch. All thestop positions of each of the devices 128, 194, 228 and 316 areprogrammed relative to the microswitch position after the autoloader ismanufactured. By using the microswitches and positioning which isrelative to the microswitches, precise stop locations for each of thedevices is reliably provided each time the autoloader control system ispowered up.

The pneumatic devices are controlled by a pneumatic source 470. Source470 includes digital I/O 457 receives digital signals from extended bus447 and outputs control signals to a solenoid interface 458. Solenoidinterface 458 is connected to a pneumatic manifold 459 such that aplurality of solenoid control the opening and closing of respectivevalves connected to each one of tubes 390, 392, 401, 403, 210, 212, 255and 257. Each of the manifolds is thus responsive to a respectivesolenoid to output air to its associated tube.

When the autoloader is initially connected to analyzer/furnace 54, aface 430 (FIG. 4) of attachment block 72 must be parallel with a face432 (FIG. 1) of purge chamber 90. Additionally, bore 365 (FIG. 17) offurnace attachment block 72 must be aligned with bore 361 of purgechamber 90. The level adjusting columns 104, 105 and 106 are adjusted toprovide appropriate orientation using columns 104, 105 and 106. Theaxial alignment of bores 361 and 365 assisted by posts 434 projectingoutwardly from face 432 of purge chamber 90. The posts are provided onpurge chamber 90 such that when attachment face 72 is positioned betweenall four posts, the central bores 361 and 365 are aligned. It isimportant that these bores be aligned so that boats 52 may slide betweenelevator 64 and analyzer/furnace 54.

The operation of the autoloader will now be described. Initially, whenthe system is set up, the technician programs the stop positions foreach of the motorized control mechanisms. The stop positions for eachmechanism are programmed by measuring the distance between each stopposition and the microswitch zeroing position associated with eachdevice. Following power up, the microcontroller moves each device to itszero position, and then moves each device to its initial position forthe loading sequence.

The operation of the system will now be described with reference toFIGS. 20A and 20B. Initially, hotel 56 is loaded with sample boats 52 asindicated in box 500. After it is loaded, an operator mounts hotel 52 onplatform 126. To mount the hotel, post 140 is inserted into recess 182in wall 166 of hotel 56. Snap connector 180 is inserted over post 146and the connector is locked. The operator then initiates a loadingsequence. In the loading sequence, the microcontroller 446 transmits acontrol signal to motor 59 through interface circuit 448 such that thehotel is moved to the column of the next sample to be loaded into thefurnace (e.g., the farthest left column if the sample is in the upperleft hand corner of hotel 64). The microcontroller also transmitscontrol signals to motors 63 and 65 via interface circuits 458 and 460,respectively, such that the hotel and the elevator move simultaneouslyto the row associated with the next sample (e.g., the first row if thesample is in the upper left-hand corner). As indicated by box 502. Themicrocontroller then transmits an electronic signal to pneumatic source460, which outputs a fluid control signal to cylinder 208 of pneumaticpush rod 62. Responsive thereto, pin 209 of pneumatic drive 208 pushes aboat 52 out of the hotel and into the lower elevator shelf 68 asindicated in block 506. Microcontroller 446 then transmits a controlsignal to motor 65 which effects lifting of elevator 64 to the top rowof the hotel if the elevator is not in that position already.

The microcontroller then determines whether a boat 52 is currently inthe furnace as indicated in decision block 508. Because theanalyzer/furnace personal computer is used to control the autoloader,the computer has boat status information stored therein. If a sample wasanalyzed, but the boat associated therewith was not removed, themicrocontroller knows that a boat is in the furnace. If a boat iscurrently in the furnace, the microcontroller outputs a control signalto interface 462 which controls motor 77 to move the boat retrieval rodhalfway into the furnace as indicated in block 510. The microcontrollerthen transmits a control signal to pneumatic source 460 which controlsrotor 400 to rotate the retrieval rod 76 and hook 33 to the up positionillustrated in FIG. 16. The microcontroller then transmits a controlsignal through interface circuit 462 to motor 77 such that push rod 76is controlled to move all the way into furnace 54, as indicated in block512. The microcontroller then transmits a control signal to pneumaticsource 470 which outputs a fluid control signal to pneumatic drive 400which effects rotation of hook 322 to the "down" position illustrated inFIG. 16. The microcontroller then transmits a control signal tointerface 462 which causes motor 77 to pull the boat retrieval rod 76and boat 52 out of the furnace and into the boat purge chamber 90 asindicated in block 514.

Microcontroller 446 then transmits a control signal to the pneumaticsource 470, responsive to which the pneumatic source transmits a fluidcontrol signal to pneumatic drives 380, 382. The pneumatic drives movethe furnace sealing plates to the released position illustrated in FIG.21, as indicated in block 516. The microcontroller then transmits acontrol signal to motor 65 through interface 458 responsive to whichelevator 64 is moved to the unload position illustrated in FIG. 21, asindicated in block 518. In the unload position, shelf 68 is aligned withbores 361 and 365. Microcontroller 448 then transmits a control signalto motor 77 via interface 462 such that the motor and rod 76 pull boat52 unto shelf 78, as indicated in block 520. The microcontroller thentransmits a control signal to source 470, which outputs a fluid controlsignal to pneumatic rotor 400. The pneumatic rotor rotates hook 322 90°to the up position, as indicated in block 522. The microcontroller thentransmits a control signal to motor 77, through interface 462,responsive to which motor 77 pulls retrieval rod 76 back to the homeposition illustrated in FIG. 8. Microcontroller 446 then transmits acontrol signal to pneumatic source 470 which outputs a fluid controlsignal to pneumatic rotor 400, responsive to which hook 322 is rotated90°, as indicated in block 524.

The microcontroller 446 then transmits a control signal to motor 65through interface 458 which effects movement of elevator 64 to the loadposition illustrated in FIG. 8, as indicated in block 526. In the loadposition, shelf 68 is aligned with bores 361 and 365. Microcontroller446 also transmits a control signal to motor 77 through interface 460,responsive to which, rod 76 and hook 322 push boat 52 into purge chamber90. Microcontroller 446 also transmits a control signal to source 470responsive to which the rotor 400 rotates rod 76 and hook 322 to the upposition. The microcontroller then transmits a control signal to motor77, responsive to which the boat retrieval rod 76 is moved back to thehome position, which is illustrated in FIG. 22. The microcontroller thentransmits a control signal to motor 65 via interface 460, responsive towhich elevator 64 is lowered to a position where it will not interferewith the movement of furnace sealing plate 70 into abutment withautoloader furnace attachment block 72, as indicated in block 528. Themicrocontroller 446 then transmits a control signal to pneumatic source470, responsive to which fluid control signals are input to pneumaticdrivers 380 and 382 which push sealing plate 70 into secure engagementwith autoloader furnace attachment block 72. The analytical furnace 54will then effect purging of the purge chamber 90 by flushing the air inchamber 90 through the analytical system as indicated in block 530.

If it was determined in decision block 508 that a boat is not in thefurnace, the microcontroller transmits a control signal to pneumaticsource 470. Pneumatic source 470 transmits a fluid control signal topneumatic drives 380 and 382, which moves the sealing plate 70 to thereleased position, as indicated in block 532. The program then proceedsto block 526. In decision block 534, the microcontroller determineswhether a boat is on shelf 78 of elevator 64. If a boat is on shelf 78,a control signal is transmitted to motor 65 through interface 460 toeffect movement of elevator 64 to its lowest, dump position as indicatedin block 536. As indicated in block 536, the microcontroller thentransmits a control signal to pneumatic source 470, responsive to whicha fluid control signal is input to pneumatic tilter 79. Pneumatic tilter79 pushes pin 253 upwardly causing rotation of box 238. The boat 52 ontop shelf 78 is dropped from the elevator shelf such that it isdeflected off shoot 84 into spent boat container 86. The microcontrollerthen inputs a control signal to input source 470 which outputs a controlsignal to tilter 79 causing the elevator to return to its rest state asindicated in block 538. The microcontroller then transmits a controlsignal to motor 65 through interface 460, responsive to which elevator64 is moved to the next sample position as indicated in block 540.Simultaneously with movement of elevator 64 to the next sample position,pusher 62 is moved to the next row if the next sample is in a differentrow than the current sample in the furnace.

The microcontroller then determines whether the purge chamber 90 ispurged as indicated in block 542. The microcontroller, which controlsanalyzer furnace 54 as described above, waits until the purge iscomplete, as indicated in block 542 before pushing the boat all the wayinto the furnace. The microcontroller then controls motor 77 to move theretrieval rod 76 such that the boat in the purge chamber is moved allthe way into the furnace as indicted in block 544. The microcontrollerthen transmits a control signal to pneumatic rotor 400 through control470, which effects rotation of the retrieval arm to the up position. Themicrocontroller then transmits a control signal to motor 77 which pullsthe boat retrieval arm back to the home position such that hook 322 ispositioned in purge chamber 90.

The microcontroller may be programmed to load any number of samples, upto the maximum number that the hotel will hold. The autoloader emptiesthe hotel from left to right, emptying each row before moving to thenext row. Accordingly, after each sample is removed, the hotel is movedto the next column. Alternatively, the microcontroller may be programmedto empty each column before moving to the next adjacent column. Ofcourse, the microcontroller may be programmed to empty the samples inany order. Additionally, where the microcontroller is implemented usingthe analyzer furnace's personal computer. It is envisioned that the userwould input the number of samples to be tested into the personalcomputer. The personal computer would display the positions wheresamples are to be loaded based upon the user wants to test.

Accordingly, it can be seen that an autoloader is disclosed whichprovides efficient loading of a plurality of samples into aanalyzer/furnace one at a time, as well as unloading of the furnaceafter each sample is tested. The autoloader provides a sealing mechanismwhich allows for the introduction of the sample and subsequent sealingof the furnace to prevent introduction of atmospheric nitrogen duringcombustion and analysis. The system includes a mechanism which pushes asample and a sample container into the furnace hot zone, retracts to acooler region of the furnace during analysis, and then returns to thehot zone to retrieve the used container. Additionally, the systemprovides a method of delivering a spent, hot boats (having a temperatureof approximately 800° C.) into a container where it will cool to roomtemperature and then may be reused or thrown away.

It will become apparent to those skilled in the art that modificationsto the preferred embodiment of the invention as described herein can bemade without departing from the preferred embodiment of the invention asdescribed herein. For example, hydraulic control system or electricmotors may be substituted for the pneumatic devices utilized in theautoloader. Additionally, the maximum capacity of the hotel could begreater than or less than forty-nine. These and other modifications tothe present invention can be made without departing from the spirit orscope of the invention as defined by the appended claims.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows.

We claim:
 1. An automatic sample loader for use with an analyticalcombustion furnace having a horizontal combustion tube comprising:afirst frame member comprising a first horizontal plate verticallyseparated from a second horizontal plate by a plurality of verticalcolumn members; a guide rail mounted on said first horizontal plate; afirst carriage member movably mounted on said guide rail; a hotel memberremovably mounted on said carriage member, said hotel member comprisinga frame having a top and a bottom member vertically spaced by attachedend members with a plurality of vertically spaced horizontal platesconnected at each end to said end members for carrying a plurality ofcombustion tools; motor means for moving said carriage member; a secondframe member attached to and vertically spaced above said first framemember; a pair of horizontally spaced vertical end plates on said secondframe member with one of said end plates having an aperture therein; apair of spaced horizontal guide rods supported by said end plates; asecond carriage member movably supported on said guide rods, said secondcarriage member comprising a furnace seal member having an aperturetherein and a guide member spaced from said furnace seal member; arotary actuator support member on said guide rods, and a rotary actuatormember carried on said rotary actuator support member; a motor on saidsecond carriage member for reversibly moving said rotary actuatorsupport member; a boat retrieval rod supported by said rotary actuatormember, said boat retrieval rod extending through said furnace sealmember, a hook member on the distal end of said boat retrieval rod, saidrotary actuator member for reversibly rotating said boat retrieval rodand hook member from a first position where said hook member extendshorizontally to a second position where said hook member extendsdownwardly; a first vertical guide rail mounted on one side of saidfirst carriage member; a first actuator member movably supported on saidfirst vertical guide rail, said actuator member comprising a pneumaticcylinder having a horizontally extendible rod member for pushingcombustion boats from said hotel member; motor means for reversiblyvertically moving said first actuator member on said first verticalguide rail; a second vertical guide rail mounted on the other side ofsaid first carriage member; and an elevator means movably mounted onsaid second vertical guide rail for receiving combustion boats from saidhotel member and for delivering said combustion boats to a positionwhere said combustion boats can be pushed by said boat retrieval rod. 2.A sample loader for a horizontal analytical combustion furnacecomprising:a frame member for attachment to the horizontal combustionfurnace comprising a first end plate having an aperture therein, asecond end plate spaced from said first end plate, and a pair of spacedparallel guide rods joining said first and second end plates together; afurnace seal member having an aperture therein movably supported on saidspaced guide rods; a closure member for said furnace seal member;reversible means for moving said furnace seal member into a sealingposition and for moving said moving said seal member away from said saidsealing position; a carriage member movably supported on said guiderods; a rotary actuator on said carriage member; a boat retrieval rodoperatively connected to said rotary actuator and extending through saidclosure member in said furnace seal member, said boat retrieval rodhaving a hook on the end thereof remote from said rotary actuator, saidrotary actuator reversibly moving said hook on said boat retrieval rodfrom an inoperative to an operative position; and a motor mounted onsaid frame for reversibly moving said carriage member.
 3. A sampleloader as set forth in claim 2, wherein said closure member comprises:abearing member for closing a combustion furnace side of said aperture insaid furnace seal member around said boat retrieval rod.
 4. The sampleloader as defined in claim 3, wherein said closure member furthercomprises a spring energized polymeric sealing member within saidclosure member for forming a substantially gas-tight seal about saidboat retrieval rod.
 5. The sample loader as defined in claim 4, whereinsaid closure member further comprises an insulating seal disc having anaperture therein for said boat retrieval rod, said insulating seal discclosing the end of the aperture in said furnace seal member remote fromsaid combustion furnace.
 6. A sample loader as set forth in claim 5,wherein said reversible means for moving said furnace seal membercomprises a pair of pneumatic cylinders, said pneumatic cylinders beingconnected between said end plate of said frame member and said furnaceseal member.
 7. A sample loader as set forth in claim 2, wherein saidfirst end plate for said frame member further includes means foraligning said first end plate, and said frame member further includingat least one latch member.
 8. A sample loader as set forth in claim 2,wherein said first end plate of said frame member has a circumferentialgroove about said aperture therein for receiving an elastic sealingmember.
 9. Sample loader for a horizontal analytical combustion furnacecomprising:a first frame for attachment to a horizontal combustionfurnace comprising a first end plate having an aperture therein; asecond end plate spaced from said first end plate; at least one guiderod extending between said first and second end plates; a first carriagemovably supported on said guide rod, said carriage comprising a furnacesealing member having an aperture therein and an end member joinedtogether by at least one side member; a closure member for said aperturein said furnace sealing member; reversible means for moving said furnacesealing member into a sealing position and for moving said seal memberaway from said sealing position; a rotary actuator member; a supportmember for said rotary actuator member movably mounted on said guiderod; a boat retrieval rod operatively connected to said rotary actuatorand extending through said closure member into said furnace seal member,said boat retrieval rod having a hook on the end thereof remote fromsaid rotary actuator, said rotary actuator reversibly moving said hookon said boat retrieval rod from an inoperative to an operative position;and a motor mounted on said first carriage for reversibly moving saidsupport member for said rotary actuator.
 10. A sample loader as setforth in claim 9, wherein said closure member comprises:a bearing formovably closing a combustion furnace side of said aperture in saidfurnace seal member around said boat retrieval rod.
 11. A sample loaderas set forth in claim 10, wherein said closure member comprises a springenergize polymeric sealing member within said closure member for forminga substantially gas tight seal about said boat retrieval rod.
 12. Asample loader as set forth in claim 11, wherein said closure memberfurther includes an insulating sealing disk having an aperture thereinthrough which said boat retrieval rod can move.
 13. A sample loader asset forth in claim 12, wherein said reversible means for moving saidfurnace sealing member comprises at least one pneumatic cylinder, saidat least one pneumatic cylinder being connected between said end plateof said frame member and said furnace sealing member.
 14. A sampleloader as set forth in claim 9, wherein said first end plate for saidframe member further includes means for aligning said end plate withsaid gas purging module on said combustion furnace and at least onelatch member on said first end plate of said frame member forcooperating with at least one latch member on said gas purging modulefor releasably fastening said first end plate and said gas purgingstation together.
 15. A sample loader as defined in claim 14, whereinsaid first end plate of said frame member has a circumferential grooveabout said aperture therein for receiving an elastic sealing member andsaid gas purging module has a circumferential groove about said aperturefor receiving an elastic sealing member.
 16. A sample loader as setforth in claim 9, wherein said motor for moving said support member forsaid rotary actuator includes:an electric motor mounted at one end ofsaid carriage; a driving gear connected to the output shaft of saidmotor; a substantially U-shaped supporting member adjustably attached tosaid end member of said first carriage; a driver gear rotatively mountedbetween the ends of said U-shaped supporting member; a belt operablycoupled to said driving and driver gears; and a clamp member on saidrotating actuator support for griping the ends of said belt andoperatively connecting said belt to said rotating actuator supportwhereby the movement of said belt will cause said rotary actuatorsupport to move.
 17. A sample loader as set forth in claim 16including:a first vertical guide rail mounted in one side of said secondcarriage member; a first actuator member movably supported on said firstvertical guide rail, said actuator member comprising a pneumaticcylinder having an extendable rod member for pushing combustion boatsfrom said hotel member; a second vertical guide rail mounted on theother side of said first carriage member opposite said first verticalguide rail; and an elevator movably mounted on said second verticalguide rail for receiving combustion boats from said hotel member and fordelivering said combustion boats to a location where said combustionboat can be pushed.
 18. A sample loader as set forth in claim 9including:a second frame for supporting said first frame, said secondframe comprising an upper horizontal plate vertically separated from alower horizontal plate by a plurality of vertical column members; and aplurality of spaced vertical leveling screws on said second frame forraising and lowering the height of said second frame and for levelingsaid second frame.
 19. A sample loader as set forth in claim 18 whereinsaid elevator comprises a carriage movably mounted on said verticalguide rail;a substantially rectangular box pivotably carried on saidspaced supporting arms; and a pneumatic cylinder operatively connectedbetween the bottom of said box and said carriage for causing said box topivot.
 20. A sample loader as set forth in claim 9 including a guiderail mounted on said lower horizontal plate, said guide rail extendingorthogonally to said combustion tube when said automatic sample loaderis attached to an analytical combustion furnace;a second carriagemovably mounted on said guide rail; a hotel member removably mounted onsaid second carriage said hotel member comprising a frame having a topand a bottom member vertically spaced by attached end members with aplurality of vertically spaced horizontal plates connected at each endto said end members for carrying a plurality of combustion boats; and amotor means for moving said second carriage member relative to saidcombustion tube.
 21. A automatic sample loader as defined in claim 20and further including a shoot depending below an aperture in said upperhorizontal plate of said second frame, for receiving a spent combustionboat from said elevator; and a collection receptacle on said lowerhorizontal plate of said second frame for receiving spent combustionboats from said shoot.